-all: $(patsubst %.txt,%.txt.dat,$(wildcard *.txt))
+all: $(foreach file,$(filter-out %sigtemplate.txt,$(wildcard *.txt)),$(file).dat)
-STRFILE=$(shell which strfile || echo touch -r)
+STRFILE=$(shell if which strfile >/dev/null 2>&1; then which strfile; else echo touch -r; fi)
%.txt.dat: %.txt
$(STRFILE) $< $@